@@ -0,0 +1,21 @@
+'use strict';
+
+// Require or import
+
+const { Logger } = require('./logger.js');
+
+class Server {
+  constructor() {
+    this.logger = new Logger();
+  }
+
+  shutdown() {
+    this.logger.log('Shutting down...');
+  }
+}
+
+// Usage
+
+const server = new Server();
+server.shutdown();
+console.log('Bye!');
@@ -0,0 +1,15 @@
+'use strict';
+
+class ServiceLocator {
+  static #modules = new Map();
+
+  static get(moduleName) {
+    return ServiceLocator.#modules.get(moduleName);
+  }
+
+  static set(moduleName, exp) {
+    ServiceLocator.#modules.set(moduleName, exp);
+  }
+}
+
+module.exports = { ServiceLocator };
@@ -0,0 +1,21 @@
+'use strict';
+
+const { ServiceLocator } = require('./2-locator.js');
+
+class Server {
+  constructor() {
+    const { Logger } = ServiceLocator.get('logger');
+    this.logger = new Logger();
+  }
+
+  shutdown() {
+    this.logger.log('Shutting down...');
+  }
+}
+
+const logger = require('./logger.js');
+ServiceLocator.set('logger', logger);
+
+const server = new Server();
+server.shutdown();
+console.log('Bye!');
@@ -0,0 +1,8 @@
+'use strict';
+
+const modules = new Map();
+
+const get = (moduleName) => modules.get(moduleName);
+const set = (moduleName, exp) => modules.set(moduleName, exp);
+
+module.exports = { get, set };
@@ -0,0 +1,3 @@
+'use strict';
+
+module.exports = new Map();
@@ -0,0 +1,8 @@
+'use strict';
+
+const modules = new Map();
+
+module.exports = {
+  get: modules.get.bind(modules),
+  set: modules.set.bind(modules),
+};
@@ -0,0 +1,9 @@
+'use strict';
+
+class Logger {
+  log(message) {
+    process.stdout.write(message + '\n');
+  }
+}
+
+module.exports = { Logger };
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+'use strict';`
	`2`	`+`
	`3`	`+module.exports = new Map();`